Six Numbers You Should Know and Why

Numbers If you’re like most people, you keep track of a lot of numbers — important numbers — not to mention passwords. I’ll apologize up front because I’m going to tell you about some more numbers you should know. They’re important because they tell you something about the state of your health.

Body Mass Index (BMI)

What BMI can tell you

BMI calculates body fat. It is a measure of your weight in proportion to your height. If your BMI is too high, you may be at increased risk for several chronic health problems, including heart disease, type 2 diabetes, gall bladder disease, osteoarthritis, sleep apnea and cancer. All in all, BMI should give you a reasonable estimate of how much body fat you have. However, it may underestimate body fat if you have low muscle mass or overestimate it if you are extremely muscular. Another problem that might get overlooked is excess abdominal fat. Your BMI might be in the normal range, but if you have excess belly fat, you may be at increased risk of heart disease.

To figure out your BMI, use this calculator from the Mayo Clinic

What the numbers mean

Less than 18.5     Underweight
18.5 to 24.9          Normal
25 to 29.9             Overweight
30 or greater        Obese

Waist measurement

What waist size can tell you

Excess belly fat is a greater risk factor for heart disease than excess fat in any other part of the body. You can have a normal BMI and still be abdominally obese.

What the CDC calls abdominally obese

Men: Waist measurement more than 40.2 inches. Women: Waist measurement more than 34.6 inches.

How to measure

Wrap a tape measure around your waist, about the level of your belly button. While you’re at it, figure out your waist-to-hip ratio, which is the size of your belly compared to the size of your hips. Divide your waist measurement by your hip measurement. A ratio of 0.8 or lower is considered normal.


What cholesterol can tell you

If you’ve got high LDL (bad) cholesterol or low HDL (good) cholesterol, your arteries may become plugged with fatty plaques, which can put you at risk of heart disease, heart attack and stroke.

What’s normal?

  • Total cholesterol — Less than 200 mg/dL
  • HDL cholesterol — Greater than 50 mg/dL
  • LDL cholesterol — Less than 130 mg/dL (less than 100 mg/dL for those at high risk for heart disease)

When to test and how often

If you are age 20 or older and have not been diagnosed with heart disease, the American Heart Association recommends having your cholesterol levels checked every four to six years as part of a cardiovascular risk assessment. You should check with your doctor about your heart disease risk and how often you should be tested.


What triglycerides can tell you

Triglycerides are a type of fat found in the blood. The body converts calories it doesn’t need right away into triglycerides and stores them in fat cells. If you have high triglycerides, which can happen if you eat more calories than you burn, you can increase your risk of heart disease — especially if you also have high LDL cholesterol.

When to test and how often

It’s recommended that you get your triglycerides checked every time you have your cholesterol checked.

What’s normal?

  • Normal — less that 150 mg/dL (the American Heart Association says 100 mg/dL is best.
  • Borderline high — 150 to 199 mg/dL
  • High — 200 to 499 mg/dL
  • Very high — 500 mg/dL

Measuring blood pressure

Blood pressure

What blood pressure can tell you

Blood pressure rises with each heartbeat and falls when your heart relaxes between beats. If your blood pressure is high it means your heart has to work harder, which increases your risk for heart disease, stroke, heart failure and kidney disease.

What the numbers mean

Systolic (Top) Diastolic (bottom)             Meaning
Below 120 and Below 80 Normal blood pressure
120-139 or 80-89 Pre high blood pressure
140-159 or 90-99 Stage 1 high blood pressure
160 or more or 100 or more High blood pressure

 When to check your blood pressure

According to the CDC, most people should have their blood pressure checked at each doctor visit, but at least every two years. If you have already been diagnosed with heart disease or have risk factors, it should be more closely monitored.

Blood sugar

What your blood sugar can tell you

If your blood sugar is high, it means that your body either isn’t making enough insulin or can’t properly use the insulin it does make, which could be a sign of diabetes or prediabetes. Insulin helps move sugar (glucose) from the blood into cells. Over time and without any symptoms, high blood sugar can damage blood vessels, nerves, the kidneys and the eyes.

Who should have blood sugar checked?

Recommendations from the American Diabetes Association:

  • Anyone with a BMI higher than 25, along with other risk factors, such as high blood pressure, high cholesterol or history of heart disease.
  • Anyone older than 45 should get an initial screening and if results are normal, be screened ever three years.

What’s normal?

A fasting glucose level or hemoglobin A1C can be done with a blood test during a routine physical. A glucose level of less than 100 mg/dL and an A1C of below 5.7 percent are considered normal.

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Diane Atwood

About Diane Atwood

For more than 20 years, Diane was the health reporter on WCSH 6. Before that, a radiation therapist at Maine Medical Center and after, Manager of Marketing/PR at Mercy Hospital. She now hosts and produces the Catching Health podcast and writes the award-winning blog Catching Health with Diane Atwood.